1. Field of the Invention
The present invention relates to a card connector assembly and particularly to the card connector assembly which reduces transmission errors due to noise and provides a function for dust settling prevention.
2. The Prior Art
Noise is inevitable during signal transmission between electrical devices connected by wires and connectors. The noise may result from electron static disturbance (ESD) or electromagnetic interference (EMI). ESD will exist on two device surfaces when sufficient particles settle thereon thus forming an electron static capacitor between the two devices which emits electron static electrons that interfere with the performance of the related devices and other peripherals. When two mating devices, such as an electrical card and a related card connector are abruptly connected together in a relatively dry environment, particles on the devices may cause an electron static discharge and damage the components within the electrical card. Noise can also result from an EMI which is related to an electric current flowing through the devices. Prior art which prevents noise from affecting the card connector are disclosed in U.S. Pat. Nos. 4,818,239; 4,878,856; 4,810,203; 5,085,590; 5,149,276; 5,176,523; 5,334,046. However, the prior art only addresses on the prevention of the ESD at the insertion opening of the connector while virtually neglecting the prevention of the EMI. More specifically, the prior art merely provides a grounding plate at two distal ends of the guiding bracket near the insertion opening of the card connector. This structure can eliminate ESD upon insertion of the electric card into the card connector but the EMI will continue to affect the operation of the electrical card. If the electrical card and an interface of the card connector having pins projected therethrough are not isolated or protected with a sufficient metal shield, these portions will be affected by EMI. Another drawback of the prior art is that the two guiding brackets are exposed to the outside environment, therefore noise will affect the assembly of the electrical card and the card connector. Additionally, dust is apt to gather on the card-connector assembly due to an insufficient metal shield thus causing ESD.
Therefore, an improved card connector is required to eliminate the above drawbacks of the prior art especially one which can considerably eliminate problems resulting from ESD and EMI.